Cell for electrolytic deposition of metals

ABSTRACT

A CELL ASSEMBLY FOR ELECTROLYTIC DEPOSITION OF METALS, DESIGNED TO FACILITATE THE ELECTROLYTIC DEPOSITION AND RECOVERY OF ZINC OR OTHER METALS SIMILARLY PROCESSED. THE CELL ASSEMBLY INCLUDES AN IMPROVED CELL BOX COMPRISING A TREATED WOODEN STRUCTURE HAVING A ONE PIECE PROTECTIVE LINER. THE LINER INCLUDES AN INTEGRAL INLET BOX AND OUTLET WEIR TO INSURE CONSISTENT SOLUTION LINE ELEVATION. AN IMPROVED CATHODE STRUCTURE IS UTILIZED, HAVING PROTECTIVE NON-CONDUCTIVE COVERINGS APPLIED THERETO ALONG THE SIDE AND TOP PORTIONS OF THE PLATE ON WHICH METAL IS DEPOSITED.   IMPROVED ANODE ASSEMBLIES INCLUDE STIFFENING PLASTIC GUIDES ATTACHED THERETO WHICH POSITION THE CATHODES RELATIVE TO THE ANODE STRUCTURES IN A CONSTANT SPACED PARALLEL RELATIONSHIP. CONTROL OF THE DEPOSITION OF METAL IS FURTHER ACHIEVED BY AN IMPROVED BUS BAR SUPPORT SYSTEM FOR THE CATHODE AND ANODE UNITS, FACILITATING ACCURATE ADJUSTMENT AND LEVELING OF THE UNITS RELATIVE TO THE ELECTROLYTE.

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efe'n N. J25 6583 United States Patent O 3,579,431 CELL FOR ELECTROLYTICDEPOSITION OF METALS Peter M. Jasberg, Kellogg, Idaho, assignor to TheBunker Hill Company, Kellogg, Idaho Filed Feb. 23, 1968, Ser. No.707,847 Int. Cl. B01k 3/00, 3/02 US. Cl. 204-275 18 Claims ABSTRACT OFTHE DISCLOSURE A cell assembly for electrolytic deposition of metals,designed to facilitate the electrolytic deposition and recovery of zincor other metals similarly processed. The cell assembly includes animproved cell box comprising a treated wooden structure having a onepiece protective liner. The liner includes an integral inlet box andoutlet weir to insure consistent solution line elevation. An improvedcathode structure is utilized, having protective non-conductivecoverings applied thereto along the side and top portions of the plateon which metal is deposited. Improved anode assemblies includestiffening plastic guides attached thereto which position the cathodesrelative to the anode structures in a constant spaced parallelrelationship. Control of the deposition of metal is further achieved byan improved bus bar support system for the cathode and anode units,facilitating accurate adjustment and leveling of the units relative tothe electrolyte.

BACKGROUND OF THE INVENTION (1) Field of the invention The inventiondisclosed herein relates to a cell assembly for electrolytic depositionof metals such as zinc. In a zinc recovery process, roasted zinc ore isleached with sulfuric acid to produce an electrolyte liquid containingzinc sulfate. The pure zinc is then recovered from the electrolyteliquid by electrolysis in a cell box, the zinc being deposited in theprocess on aluminum cathode plates which form part of a series circuitthrough the electrolyte to anode plates conventionally fabricated from alead and silver alloy. The deposited metal is periodically stripped fromthe cathode plates and processed further to produce bulk metal formanufacturing processes.

(2) Description of the prior art Conventional cell assemblies forelectrolytic deposition of metals such as zinc have requiredconsiderable manual effort. Control of the deposition of metal on thecathodes has been rather unrefined, and the resulting inconsistency inthe area and nature of the deposited metal has been accommodated bymanual effort. The stripping of the cathodes, when carried out manually,can adapt to variations in the height of metal on the cathode caused bychanges in the level of electrolyte and variations in deposited metalthickness. These variations are most difiicult to accommodate in amechanical or automated system of cathode stripping. The principalpurpose of the present development is to provide a cell that canaccommodate automated handling of the cell elements and mechanizedstripping of metal deposited on the cathodes.

The manual handling of cell components has permitted the use ofexpendable wooden guides for the cathodes and anodes in a cell box,since the person positioning the elements can visually recognize andmanually accommodate variations in the guides due to wear and warping ofthe members. However, more rigid control of a consistent location ofeach member is required in order to develop an efficient mechanicalsystem of handling these elements.

Cell assemblies conventionally have required a considerable amount ofmaintenance due to inefficient flow characteristics of the electrolytein the cell, resulting in areas of reduced liquid movement that causesolid deposits to foul the cell, necessitating frequent cleaningoperations. Manual stripping of the cathodes, besides requiring a largework force of generally unskilled labor, results in considerable damageto the cathodes and constant replacement of these rather expensiveelements. The present assembly provides a complete integratedcombination of improved elements in such a cell to improve cellefficiency and to adapt the electrolytic recovery system to automatedmethods of handling the desired metal.

SUMMARY OF THE INVENTION The present invention basically comprises acompletely redesigned cell for electrolytic deposition processes. Inthis cell, an improved cathode, having a partially covered and insulatedplate structure, is precisely spaced between improved anodes bynon-conductive guides that extend the full height of the anodestructures and which are attached to them to provide required stiffeningof the anodes. The positioning and confinement of the cathodes by theanodes and anode guides provides improved liquid flow characteristics inthe cell assembly. The cell box itself is constructed with an integralliner including an inlet box and outlet weir designed for optimumhandling capability. The anode structure, including the stiffening guideelements, is designed for the best liquid flow and maximum anode-cathodesurface area relationships to control the coating of metal on thecathode and to prevent excess deposition, particularly along the top andside edges of the cathode area that is to be coated with the depositedmetal. Control of the level of the electrolyte is provided, and accurateleveling of the anodes and cathodes is insured, by an improvedadjustment apparatus designed into the bus bar assembly at each side ofthe cell.

It is a general object of this disclosure to provide improvedoperational characteristics in the cell assembly by insuring accurateanode to cathode spatial relationships and by proper insulation of theanode and cathode units to provide more etficient electrolyticdeposition in a given cell structure. The combination disclosed hereinis designed specifically for adaptation to mechanical handlingtechniques for removing and replacing cathodes and anodes in relation tothe cell and in relation to associated mechanical processing devices,such as stripping equipment and washing mechanisms. The unit is designedto increase production of cell assemblies and to extend the useful lifeof each cell component. The structure reduces the maintenance andmanpower requirements in electrolytic recovery assemblies as knowntoday. The entire combination has been developed to produce a stablesystem to which modern methods of automation can be adapted as itsdevelopment progresses.

A primary object of the cell assembly disclosed herein is to provide acell structure for the deposition of metal which is adaptable tohydraulic stripping of the deposited metal in the manner disclosed in myco-pending application, Ser. No. 636,797, no w Pat. No. 3,501,385,Process for Stripping Metal From a Cathode. Hydraulic stripping requiresaccurate control of the position and amount of deposited metal on thecathode plate, which are fundamental requirements guiding the designedstructural features of all the elements disclosed herein.

Another object of the invention is to facilitate automation of celloperation by providing uniformity in the cathode and anode locationswithin the cell, uniformity in the elevation of the solution line ofelectrolyte maintained within the cell and consistent metal depositionand control of the area of metal deposition on the cathode plates.

Another object of the invention is to provide an improved anodestructure designed for longer life and maxi mum material usage. Theanode structure provides an attached guide for the cathodes to insureproper cathodeanode separation and to provide a restricted verticalchimney in the electrolyte between adjacent cathodeanode units.

One object of the invention is to minimize cell maintenancerequirements. This is accomplished by more effective design of the anodeand cathode units and by providing improved electrolyte flowcharacteristics in the cell. Maintenance is also relieved by moreeffective protection of the cathode and anode surfaces by use of covermaterials and non-abrasive plastic guide structures.

Another object of the invention is to insure proper deposition of metalalong the upper portion of the cathodes by providing accurate adjustmentof the cross level orientation of the cathode and anode units. This isprovided by an improved bus bar adjustment feature that simultaneouslypositions both the contact and heel ends of the header bars that supportthese units.

Another object of the invention is to provide within the cell animproved cathode structure having covered side and top areas whichcontrol the area of metal deposition and reduce damage to the vulnerablecathode surfaces during insertion or removal from the cell. The coveredareas, together with the remaining portions of the cell assembly,increase the amount of metal deposition at the top of the cathode tofacilitate hydraulic stripping operations.

Another object of the invention is to provide an improved cell boxstructure including a one piece liner having integral inlet box andoutlet weir structures This eliminates problems of leakage and corrosionand provides a liner apparatus that can be adapted to existing boxstructures during modification of a cell line.

These and further objects will be evident from the following detaileddisclosure, particularly in view of the claims at the conclusion of thisspecification. The mechanical and physical details of the apparatus asdisclosed herein are not intended to limit the scope of the inventiondisclosed, which is set out in the language of the claims.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a top view of a complete cellassembly, portions of the adjacent cell assemblies being broken away atthe respective sides thereof;

FIG. 2 is a vertical sectional view taken along line 22 in FIG. 1;

FIG. 3 is a vertical sectional view taken along line 3--3 in FIG. 1;

FIG. 4 is an end view, at a reduced scale, of the inlet end of a singlecell box;

FIG. 5 is an end view opposite to FIG. 4;

FIG. 6 is a fragmentary horizontal sectional view illustrating thecathode-anode spatial relationship;

FIG. 7 is a view illustrating the fabrication of the cathode unit;

FIG. 8 is a somewhat simplified view illustrating the position of thetop portion of a cathode unit in a cell box;

FIG. 9 is a vertical sectional view taken along line 9-9 in FIG. 7 at anenlarged scale, the central portion of the cathode unit being brokenaway;

FIG. 10 is a further enlargement along a vertical plane through acathode unit adjacent to the solution line, illustrating the depositionof metal on the cathode faces;

FIG. 11 is a view illusrating the fabrication of an anode unit;

FIG. 12 is a side view of an anode guide;

FIG. 13 is an end view of the anode guide shown in FIG. 12;

FIG. 14 is a side view of the anode guide opposite to that shown in FIG.12;

FIGS. 15 through 18 are enlarged cross sectional views taken along lines15-15 through 18-18 respectively in FIG. 12;

FIG. 19 is an enlarged vertical sectional view taken along a transverseplane through the center of an anode unit along the side portionthereof, the remainder of the anode unit being broken away;

FIG. 20 is a somewhat simplified view taken similarly to FIG. 3,illustrating the insertion of a cathode unit between adjacent anodeunits;

FIG. 21 is a fragmentary end view and cross sectional view through thecell assembly, illustrating specifically the adjustable supports for thebus bars;

FIG. 22 is a longitudinal sectional view taken along line 22--22 in FIG.21;

FIG. 23 is an enlarged sectional view showing a single bus bar supportas seen along line 2323 in FIG. 22;

FIG. 24 is a sectional view through a bus bar as seen along line 2424 inFIG. 22; and

FIG. 25 is a fragmentary vertical section view taken along line 2525 inFIG. 23, illustrating the relationship between the support and the busbar.

PREFERRED EMBODIMENT OF THE INVENTION The disclosure herein comprises acell assembly having an arrangement of liquid electrolyte cell box,cathodes and anodes with guides and lateral supports therefor, andsupports for electric current carrying bus bars. It also includeselectrolyte inlet and outlet means capable of regulating the liquidlevel in the cell.

Each anode is in the form of a tapered grid with an integral header barand an attached insulating guide at each side thereof. The anode guidesare spaced to receive cathode plates therebetween and have apertures tostraddle the header bars of the anodes. One end of each anode header barhas a downwardly opening V-notch to receive the top edge of the bus barso the header bar may conduct current to the anode.

Each cathode plate includes a cast aluminum header bar which joins theplate at the top. This header bar includes ears by which it may belifted and a notched end similar to the end of the anode header bar toengage the currentcarrying bus.

The cathode plate has an electrically non-conductive peripheral coveringwhich is impervious to the electrolyte. This peripheral covering extendsacross the top of the plate and down the vertical edges to define ametal deposit area on each side face of the plate. A suitable coveringis a polyvinyl chloride resin sold under the trade name Paraline. Thiscovering acts as a protector of the edges of the cathode plate and ofthe air-solution line adjacent the header bar. This air-solution line isthe most vulnerable area on the cathode for attack by the electrolyte.The bottom edge of the cathode plate is channelled to preventgrow-around of the metal plated thereon from one side to the other.

The electrolyte, containing metal to be deposited on the cathode, ispoured in over one end of the cell and has a temperature that is belowthe temperature in the active deposit zone between anodes and cathodeswithin the cell. The level of electrolyte in the cell is indicated inthe drawings by the line A. The assembly of anodes, anode guides andcathode plates provides vertical channels through which the electrolyte,warmed by the current and the deposition reaction, can rise. The anodeguides have apertures at the top through which the warm electrolyte canflow out toward the side cell walls. Here the liquid cools and flowstoward the discharge end of the cell. The cell has an overflow weir atthe end opposite the inlet weir to discharge spent electrolyte and tomaintain the proper solution line level of electrolyte within the cell.

THE CELL BOX The construction of each cell box is best seen in FIGS.1-5. The structure can be fabricated as shown, or might be modified fromexisting cell box structures.

The cell 1 may be of any suitable material. Wood has been widely used.The cell is rectangular and as shown, comprises a base of bottom planks2 on which side planks 3 are supported. The bottom planks 2 are carriedon sills 4. Rods 5 extend from the sills 4 to the top side planks 3 andare threaded to receive nuts 6 to clamp the side planks tightlytogether. The top side planks and the sills are counterbored so that therod head and threaded end are inset. The top counterbores are filledwith asphalt or other suitable sealer. End planks 7 are set into theside faces of the side planks. These end planks 7 are backed by verticalstuds 8 which secure them into end panels. Rods 9 extend through thestuds 8, through the ends of the side planks 3 and through coated steelstraps 10. The top plank of the side planks 3 is rabbeted out to receivea load bearing angle iron 11 which is covered with a protective coatingof an insulation material impervious to the electrolyte. Angle iron 11distributes bearing loads along the cell and also prevents the uppercell box edges from bowing outwardly.

The cell body described is provided with a one-piece liner 14 which iscomposed of electrically non-conductive polyvinyl-chloride resin soldunder the trade name of Paraline by the Barber-Webb Company. Any othersuitable electrically non-conductive material that is impervious to theelectrolyte used may be substituted for the polyvinyl-chloride resin.

The liner 14 fits the interior surface of the cell 1 and includes adrain tube portion 15 that fits in a drain outlet 12 of the cell used toempty the cell box during repair cycles. The drain outlet is a leadnipple 12 set in one of the bottom planks 2. The tube 15 extends beyondthe lead nipple. A drain hose (not shown) is fitted over nipple 12. Aplug valve 17 with a polyvinyl coated stem 18 closes the drain.

It will be noted from the drawings (FIG. 2) that the top end of plank 7ais cut on a taper across its top surface. The liner 14 has an inlet box19 formed at the corresponding end thereof. The liner inlet box 19expands toward the cell so that charged electrolyte poured into the cupportion 20 of the inlet box 19 will spread out and flow evenly into thecell 1 across the width thereof. The liner 14 has an outlet weir 21 atits other end to fit over the topmost plank 7b at the discharge end ofthe cell. Note that the plank 7b has its top surface tapered downoutwardly from the inner edge thereof. The central portion of the plankis cut lower than the ends to receive the weir 21. The weir 21 is anunderflow weir that in practice retains froth on the electrolyte surfaceto reduce the emission of gas and mist from the cell box to thesurrounding environment. The weir 21 has a tulubar outlet 23 forattachment of a drain hose 24 (FIG. 5). The hose 24 is also ofpolyvinylchloride resin. It can be expanded by heat and slipped over theoutlet 23. When it cools a fluid tight joint is established betweenoutlet 23 and hose 24. The liner 14 laps over the top side planks 3 andthe end planks 7a and 7b as shown.

ANODE ASSEMBLY The anode comprises a grid-type anode plate 25 which forzinc recovery is a lead-silver alloy and a header bar 26, which is madeup of a copper insert 51 and a leadsilver alloy cover. The cover ofinsert 51 and the plate 25 are cast integrally. The anode plate 25decreases in cross sectional thickness from the top to the bottom toreduce weight. It also has enlarged ribs 27 and 28 of constant thicknessalong the vertical side edges for stiffening and for securing the anodeguides 31 and 32. The ribs 27 and 28 are tapped at 29 to receivemounting screws which are of polyvinyl-chloride resin of a hardnesssufficient to self-thread in the lead-silver alloy of the ribs 27 and28.

Anodes have conventionally been cast in two pieces, the header bar beingwelded or otherwise fixed to the grid as a final assembly operation. Asshown in FIG. 11, the

6 anode disclosed herein can be cast as an integral unit, requiring onlythe final assembly of the side guides to the structure. By making aheavier anode than is conventional, warping and distortion of the anodegrid is minimized and much longer life can be achieved than is normal inthe industry.

Construction of the anode begins with the forming of a transverse copperinsert 51, whose surfaces are machined and pre-tinned before being castintegrally in the header bar of the anode structure. After casting ofthe anode plate 25 and header bar 26, only a small notched portion ofthe insert 51 remains exposed, this being designated by the numeral 51a.This notched portion is utilized for direct electrical contact with thebus bar in the cell assembly. The final assembly step, shown to theright in FIG. 11, is mounting of two vertical anode guides, one being ateach side of the anode plate 25 and each straddling the integral headerbar 26. These guides, designated by the numerals 31, 32 are attached bythe mounting screws mentioned above.

The anode guides 31 and 32 are molded of polypropylene. They areidentical. The guide has a head portion 33 which is curved on oppositesides to converage at a ridge 34 at the top. The curved side surfaces 35and 36 act as guides for cathode plates when the plates are lowered intothe electrolyte. The head 33 has an aperture 37 to receive the headerbar 26 of the anode 25. Below the opening 37 the guide has a centralchannel 38 which extends to the lower end of the guide. This channel 38receives the anode rib therein. The guides 31 and 32 are narrowed fromthe top to the bottom and are hollowed out to reduce the total weight.The ribs along each guide serve to stiffen the anode plates 25. The sidefaces 35a and 36a are parallel to space cathode plates on opposite sidesof the anode equidistant from the anode. The guides are flared outwardlyto engage the side edges of the wider cathodes. In this manner a widerarea of the cathode is exposed to the more narrow width of the anodeface, resulting in reduced current density along the vertical side edgesof the cathodes, eliminating excess deposition of metal or treeing inthis area. Close to the upper end of the channel 38 each anode guide hastwo apertures 39 and 40 to permit circulation of electrolyte through theguides.

C'ATHODE ASSEMBLY Referring now to the cathode plate 41 and its headerbar 42, the construction of the plate and the way in which thisconstruction cooperates with the anode guide construction will bedescribed. The cathode plate is usually, for zinc recovery, arectangular sheet of aluminum made to quite rigid specifications as topurity and flatness of surface. Its fabrication steps are as shown inFIG. 7. The bottom end of the sheet is slotted as shown at 42a (FIG. 9)with a slot inch wide and inch deep. The cathode plate is slightly wider/2 inch on each side) and extends downwardly a slightly greater distanceinch) than the exposed anode area to improve deposition characteristicsof the metal. Less metal will thereby be deposited along the side andbottom edges. The plate thickness usually is of the order of slightlyless than /5 inch. This cathode plate 41 is welded to the precastaluminum header bar 42 which has a copper insert 43 cast therein at oneend. The copper insert 43 has a downwardly opening V-notch exposed toengage a bus bar. The header bar has two hooks 44 for lifting andlowering the cathode plate.

The cathode plate 41 has apertures 45 drilled therethrough from side toside along the side edges 46 and 47 within about /4 inch of the edge andacross the solution line area (FIG. 7). The cathode plate 41 is thenprovided with continuous edge coverings 48 and 49 extending inwardbeyond the apertures 45 and filling them. The coverings are joinedacross the top of the plate 41 by cross coverings 50 at the solutionline some two to four inches below the junction of the header bar 42with the plate 41. These cross coverings 50 are of sufiicient width tocover variations in height of solution and splash coverage. A band fourinches wide is adequate.

The coverings 48, 49 and 50 are composed of polyvinyl chloride resin orother suitable electrically non-conductive material. The Paralineproduct mentioned above has proven to be satisfactory. The thickness ofthe coverings 48 and 49 prefreably is at least .030". The coverings 50,however, are preferably .015 to .020. To apply the coverings the area tobe covered is sandblasted to clean it, then coated with a primer andfinally coated with the covering which is then cured in the usual mannerof curing polyvinyl-chloride resin coatings.

CELL ASSEMBLY AND OPERATION It will be noted from the drawings,particularly FIGS. 1, 2, 3 and 6 that the spacing of the anode guides 31and 32 snugly receives the cathode plates 41 and header bars 42 betweenadjacent anode guides 31, 32. The cathode plates 41 fit between theanodes 25 with the portions covered by the coverings 48, 49 engaged bythe anode guides. This construction provides accurate and consistentcathode placement that permits the guided insertion and removal of thecathode plates 41 in a group of several plates by means of a lifter thathas jaws closing on the hooks 44.

The coverings 48, 49 and 50 define deposit receiving areas on both sidesof each cathode plate. The slot 43 prevents appreciable bridging of thedeposit from one side of the plate to the other. The covering 50establishes a line where the deposit stops on the plate surface. Asshown in FIG. 10, the deposit of metal extends outwardly below thesolution line at the lower edge of covering 50. This facilitates entryof a hydraulic jet along arrow 52 for stripping purposes.

The assembly of anodes, anode guides and cathode plates with coveredside edges provides a means of establishing well-directed upwardcirculation of the electrolyte by forming a chimney between anodes andcathode plate surfaces. The electrolyte confined in each verticalchannel along the cathode side plates is warmed by the depositionreaction and rises as indicated by the flow arrows B in FIG. 2. Fresh,cool electrolyte flowing down from the inlet weir 19 moves along thebottom of the cell 1 and upward between anodes and cathodes to the toplevel of the liquid and flows out through the apertures 39 and 40 in theanode guides 31 and 32 as well as through the slight clearance betweenthe cathode coverings 48 and 49 and the sides faces 35a and 36a of theanode guides, as indicated by the arrows B in FIG. 20. This circulationmakes efiicient use of the electric current in depositing the metal inthe electrolyte on the cathode plates and provides for movement of thespent electrolyte toward the outlet end of the cell 1 along the sidesthereof. This arrangement also permits removal and insertion of cathodeplates without cutting off the electric current. If a cathode plateswings toward an anode only the non-conducting anode guides and sideedge coverings of the cathode plates contact each other. The rathercomplete and constant liquid circulation in the cell prevents deposit ofsolids and minimizes the necessity of emptying and cleaning the cellbox.

B'US BAR SUPPORTS The cross leveling of the anodes and cathodes in thiscell assembly is critical in order that the deposition of metal alongthe upper portion of the side faces of each cathode be as constant andconsistent as possible. Consistency in the deposition of metal in thisarea as shown in FIG. is critical for purposes of successful hydraulicstripping operations. To maintain the anode and cathode units in a leveltransverse position while suspended in the electrolyte, there isprovided an improved vertical adjustment for the bus bar assemblies.

To understand the nature of the support provided for each bus bar,reference will be made to FIGS. 21-25. As

shown in FIG. 21, the heel ends of the header bar 42 of each cathodeassembly are supported right by an insulated member on the bus bars 53,which also support the anode header bars 26 of the adjacent cells. Thesame is true of the anode header bars 26, the heel ends of the anodeheader bar and cathode header bars in a cell being insulated from thesupporting bus bar not contacted by them, and as explained below, arepreferably adjusted elevationally along with the respective bus bars forthe opposite elements.

Each bus bar 53 is a solid conductive plate having adequate physicalstrength to support the header bars engaged upon it during use. Most ofthem extend only along the length of a cell box. However, certain busbars (shown at 53a in FIGS. 1 and 3) are enlarged in cross section andextend longitudinally from the box to assist in forming a shunt acrossseveral cell boxes during a repair cycle. These enlarged bus bars aresupported and function in a manner identical to the normal bus bars 53and therefore the following description of the bus bars 53 is equallyapplicable to the bars 53a.

The general features of the support apparatus are shown in FIGS. 21 and22. Each bus bar 53 is carried by a pair of U-shaped metal saddles 54 atthe respective ends of the bus bar. The saddles in turn are rigidlyjoined to longitudinal angle irons spaced transversely and extendingoppositely from one another. These angle irons are designated by thereference numerals 55. The bus bar 53 rests within the saddles 54 andbetween the angle irons 55. Prior to receiving the bus bar 53, thefabricated assembly of two saddles 54 and two angle irons 55 is coatedentirely with polyvinyl chloride resin for insulating and corrosionprotection purposes.

When assembled, the saddles 54 rest on the upper edges of the sideswalls of two adjacent cells 1. These saddles 54 rest on adjustable shims56 which are utilized to level the bus bars 53. The saddles 54 can belifted by a lever during shim adjustment. The angle irons 55 arefastened along the entire length of each bus bar 53 by a series ofscrews 57. The weight of the bus bar is also distributed to the saddles54 by means of an insulating spacing member 58 at the bottom of each busbar.

To maintain the bus bar 53 in a constant transverse orientation so thatthe spacing between bus bars 53 does not change, there are utilizedlarge wooden beams 60 that span the ends of the cell 1. Each beam 60 hascarefully spaced slots 61 along its lower surface within which isreceived the upper edge of the respective bus bars 53. The beams 60 aresecured by bolts 69 having their respective bars welded to the flangesof saddles 54 (FIG. 21) and are therefore moved upwardly as a unitduring vertical adjustment of the saddles 54 and bus bars 53.

Each of the alternated anode and cathode units includes a supportingheader bar having a contact end that rests on a bus bar 53 and a heelend that conventionally rests on the opposite side of the cell on aninsulated surface. As shown, the heel ends of the header bars not inelectrical contact with a particular bus bar 53 are supported by theoutwardly protruding ledge of the angle iron 55 fixed to the bus bar.Each bus bar 53 has two of these ledges, each extending outward inopposite directions. The upper surface of each ledge is provided with alongitudinal insulating strip 59 or 62 to support the heel ends of theheader bars of the anodes and cathodes respectively. Each is relievedbelow the contact ends of the header bars that freely pass over them.Thus, if a bus bar becomes misaligned, one need only vertically adjust asingle bus bar 53 to vertically reposition the anodes and cathodes ofadjacent cells in an accurate relationship with one another, since theanodes and cathodes move simultaneously. This eliminates the possibilityof a cathode being cocked angularly relative to an adjacent anode, acondition which frequently results in treeing of the deposited metal andwhich sometimes results in a short circuit within a cell.

The prime purpose of the various components discussed above is toprovide optimum metallurgical characteristics in the electrolyticrecovery process carried out in the cell assembly. The accurate spacingand relative location of each cathode and anode serves to assist incontrolling the rate and distribution of metal on the cathodes. Therelative area dimensions of the cathode and anode plates below thesolution line minimizes destructive treeing of deposited metal andresultant shorting of the circuits within a cell. The componentstherefore have a longer service life than is normally expected. Theimproved flow pattern of electrolyte as discussed above maintains theliquid in constant circulation and minimizes the collection of solids instill areas, thereby lengthening the period between cleaning cycles.These desirable results contribute toward improved recovery efliciencyin addition to the provision of components adapted for automatedhandling and stripping.

Having thus described my invention, I claim:

1. A cell assembly for electrolytic deposition of metals comprising anupwardly open box having an inlet for receiving electrolyte liquid andan outlet for discharging electrolyte liquid spaced across the box fromeach other;

a plurality of plate-like anodes suspended in the box, each embodying aheader bar for supplying current thereto;

an electrically non-conductive anode guide extending along each verticaledge of each anode and including opposed side faces spaced from theanode on both sides thereof;

said anode guide faces of each two adjacent guides being injuxtaposition but spaced apart a distance adequate to receive a cathodeplate between the adjacent giudes;

a cathode plate interposed between each pair of said anodes, the cathodeside edges being juxtaposed between the corresponding anode guide sidefaces; and

electrically non-conductive coverings on the said side portions of thecathode plates that are between the anode guide side faces.

2. The cell defined in claim 1 wherein the anode guides are aflixed toand carried by said anodes.

3. The cell defined in claim 1 wherein the anode guides and anodessubstantially enclose the non-covered surfaces of the cathode plates andthe anodes are spaced from the cathodes to provide a channel at eachside of each cathode plate.

4. The cell defined in claim 3 wherein the anode guides are aperturedadjacent to the upper end of the non-covered cathode plate surface ofeach cathode to permit escape of electrolyte after rising along saidnon-covered surfaces.

5. The cell defined in claim 1 wherein the anode guides are formed withconverging curved guide surfaces extending down from the top thereof todirect a cathode plate between the anodes.

6. The cell defined in claim 1 wherein the cathode plate has anon-destructive covering on both side faces extending across the upperend of the plate from one of said side portion coverings to the other.

7. In combination with a cell box for electrolytic deposition of metalshaving an inlet and outlet for electrolyte to maintain the solution lineof the electrolyte within the box at a fixed location, the improvementscomprising:

a plurality of anode assemblies suspended in the cell box by conductiveheader bars;

and a plurality of cathode assemblies suspended in the cell box byconductive header bars individually interspersed between pairs of saidanode assemblies, each cathode assembly having opposite face surfacesdirected toward the respective anode assemblies adjacent thereto;

guide means to space each anode assembly from the adjacent cathodeassemblies;

and a cover applied to the face surface of each cathode across the topportions of the face surfaces and continuing along the side edges of thecathode to the lower end thereof.

8. The apparatus set out in claim 7 wherein said guide means comprises apair of transversely spaced guide members of insulating material mountedat each side of each anode assembly and extending outward from the facesurfaces thereof.

9. The apparatus in claim 8 wherein the covers along the side edges ofeach cathode are transversely overlapped by the guides of the adjacentanode assemblies.

10. The apparatus in claim 9 wherein the lower ends of the cathode andanode assemblies terminate short of the bottom of the cell box, andwherein the side covered edges of the cathodes transversely overlap andare in juxtaposition with the guides of the adjacent anode assemblies.

11. The apparatus in claim 7 wherein the cover across the top portionsof the cathode assemblies extends below the solution line within thecell box.

1.2. The apparatus in claim 7 wherein the guides on said anodeassemblies are set inwardly from the sides of the cell box and areapertured at each side thereof at an elevation slightly below thesolution line Within the cell box.

13. In a cell for electrolytic deposition of metals wherein the metal isdeposited upon a cathode plate, an anode assembly comprising:

a transverse header bar of electrically conductive material;

a plate-like member of a suitable conductive material suspended rigidlyfrom the header bar and having transversely spaced outer side edgesdefining Wide faces;

and a pair of rigid insulating guides fixed to said platelike memberalong the respective side edges thereof, said guides extending outwardbeyond the faces of said plate-like member at each face thereof.

14. An assembly as set out in claim 13 wherein the portion of saidplate-like member adjacent the side edges thereof is of constantthickness, the faces of said member between such portions being taperedin thickness downwardly from an initial thickness equal to said constantamount.

15. An assembly as set out in claim 13 wherein the header bar andplate-like member are cast integrally.

16. An assembly as set out in claim 13 wherein the guides extend overand engage the side surfaces of said header bar, the upper ends of theguides being tapered inwardly.

17. An assembly as set out in claim 13 wherein each guide is aperturedat the respective sides of the plate adjacent the upper end of theplate.

18. An assembly as set out in claim 13 wherein the guides engage theside edge surfaces of the plate and overlap a portion of the sidesurfaces of the plate ex tending inwardly from the side edge surfaces insurface to surface contact.

References Cited UNITED STATES PATENTS 745,412 12/ 1903 Blackman 2042861,250,757 12/ 1917 Antisell 204286 1,501,692 7/1924 Ward 2042862,443,112 6/ 1948 Morin 204267 TA-HSUNG TUNG, Primary Examiner A. C.PRESCOTT, Assistant Examiner US. Cl. X.R. 204280

